You have an offer on the table. The gross salary is 8 million won higher than what you earn now. How much more actually reaches your account each month?
If you divided 8 million by twelve and got 670,000, you overshot by a wide margin. Between gross and net sit Korea's four major insurances and income tax, and their share grows as the salary does. Going into a negotiation without that structure in mind means deciding on a number that does not exist.
The deduction structure, in real numbers
Two payslips as of August 2026, both assuming a 200,000 non-taxable allowance, one dependent (yourself) and 100% withholding.
| Item | 36,000,000 / year | 52,000,000 / year |
|---|---|---|
| Gross monthly pay | 3,000,000 | 4,333,333 |
| National Pension | 133,000 | 196,333 |
| Health Insurance | 100,660 | 148,593 |
| Long-Term Care | 13,227 | 19,525 |
| Employment Insurance | 25,200 | 37,200 |
| Income tax | 65,545 | 228,127 |
| Local income tax | 6,555 | 22,813 |
| Total deductions | 344,187 | 652,591 |
| Monthly take-home | 2,655,813 | 3,680,742 |
Net comes to roughly 88.5% of gross at 36 million and about 85% at 52 million. The salary rose 44%, but total deductions rose 90%. Because income tax is progressive, the higher the salary, the smaller the share of each raise that survives to your account.
Back to that offer: a gross increase of 8 million works out to a little over 500,000 a month in hand.
How each line is calculated
The four major insurances are split between employee and employer. The 2026 employee shares are:
- National Pension 4.75%: the combined rate rose from 9% to 9.5% in January 2026, split evenly between employee and employer. This is the first year of the phased increase under Korea's pension reform.
- Health Insurance 3.595%: half of the combined 7.19%.
- Long-Term Care = Health Insurance premium × 13.14%: note that it multiplies the health premium, not your income. Expressed against income it works out to 0.9448%.
- Employment Insurance 0.9%: the unemployment benefit portion, unchanged since July 2022.
Only the National Pension has a ceiling and a floor. From July 2026 through June 2027 the standard monthly income ceiling is 6,590,000 and the floor is 410,000. Once monthly taxable income passes the ceiling, the pension contribution stops rising at 313,025.
Tax is withheld each month according to the National Tax Service's simplified withholding table, with local income tax following automatically at 10% of the income tax.
Running the numbers takes one input in the salary net pay calculator. Every figure in the table above came from it, and the page shows which date's rules were applied and when the data was last verified.
Three things people get wrong
"The non-taxable allowance only saves tax." It does more than that: it lowers the income base used for the insurances too. Setting the non-taxable amount to zero in the 52 million case drops monthly net to 3,633,164, so that single 200,000 meal allowance is worth 47,578 a month and 570,936 a year. Two offers with identical gross salaries can pay differently once the non-taxable split differs, which makes it something to ask about explicitly.
"Choosing 80% withholding means paying less tax." It does not. The 80 / 100 / 120% options change only how much is withheld each month; the total annual tax is the same either way. At 80% you take home slightly more monthly and are more likely to owe at year-end settlement; at 120% the reverse. It is a question of when you receive the money, not how much.
"The pension contribution is based on my current salary." It is not. The standard monthly income for the National Pension is set each July from the previous year's earnings. Right after a large raise, the pension premium actually billed comes out lower than the calculator shows, and the new income only takes effect the following July.
When not to rely on this calculation
An estimate is good enough for framing a negotiation range and comparing offers. These situations are different:
- When bonuses or performance pay are a large share of the package: the assumption of equal monthly pay breaks down, and deductions shift sharply in months when a bonus lands.
- Months when you join or leave mid-period: pro-rated pay and separate premium assessment rules apply.
- Predicting your year-end settlement: this covers monthly withholding only. Medical expenses, donations and housing deductions are not modelled, so it says nothing about a refund or additional payment.
- Freelancers, daily workers and company representatives: either outside the four major insurances or assessed differently. The 3.3% business income withholding structure is a different calculation entirely.
- When you need an exact figure: for a loan application or a tax filing, get the confirmed number from your payroll department or Hometax.
In short, an estimate is a tool for getting your bearings before a decision, not a substitute for a payslip. Keep that line clear and you can answer "what does that offer actually pay?" in a few seconds, mid-conversation.